using System;

using Org.BouncyCastle.Asn1;

namespace Org.BouncyCastle.Asn1.Cms
{
	public class Attribute
		: Asn1Encodable
	{
		private DerObjectIdentifier	attrType;
		private Asn1Set				attrValues;

		/**
		* return an Attribute object from the given object.
		*
		* @param o the object we want converted.
		* @exception ArgumentException if the object cannot be converted.
		*/
		public static Attribute GetInstance(
			object obj)
		{
			if (obj == null || obj is Attribute)
				return (Attribute) obj;

			if (obj is Asn1Sequence)
				return new Attribute((Asn1Sequence) obj);

			throw new ArgumentException("unknown object in factory: " + obj.GetType().Name, "obj");
		}

		public Attribute(
			Asn1Sequence seq)
		{
			attrType = (DerObjectIdentifier)seq[0];
			attrValues = (Asn1Set)seq[1];
		}

		public Attribute(
			DerObjectIdentifier attrType,
			Asn1Set             attrValues)
		{
			this.attrType = attrType;
			this.attrValues = attrValues;
		}

		public DerObjectIdentifier AttrType
		{
			get { return attrType; }
		}

		public Asn1Set AttrValues
		{
			get { return attrValues; }
		}

		/**
		* Produce an object suitable for an Asn1OutputStream.
		* <pre>
		* Attribute ::= SEQUENCE {
		*     attrType OBJECT IDENTIFIER,
		*     attrValues SET OF AttributeValue
		* }
		* </pre>
		*/
		public override Asn1Object ToAsn1Object()
		{
			return new DerSequence(attrType, attrValues);
		}
	}
}
